No-voltage circuit-breaker for alternating current.



0 (LEADEAU.

BIO-VOLTAGE CIRCUIT BREAKER FOE ALTERNATING CURRENT.

APPLICATION FILED JI ILY 27,1909.

Patented Feb. 25, 1913.

UNITED STATES Parana @FFIQE.

CHARLES C. BADEAU, 013 BOSTON, MASSACHUSETTS, ASSIG-N'UR T0 SEARS B.CONDIT,

JR., OF BOSTON, MASSACHUSETTS.

Specification of Letters Patent.

Patented Feb. as, rare.

Application filed July 27, 1909. Serial No. 509,920.

To all whom it may concern:

Be it known that I, CHARLES C. BADEAU, a citizen of the United States,residing at Boston, in the county of Suffolk and State of Massachusetts,have invented an Improvement in No-Voltage Circuit-Breakers forAlternating Currents, of which'the following description, in connectionwith the accompanying drawings, is a specification, like letters on thedrawings representing like parts.

One of the principal objects of my invention is to prevent the hummingnoise common in this class of instruments, which is commonly due to thefact that the power supply of the usual single-phase alternating currentno-voltage magnet is pulsating, while the opposing force, 1 c. theweight of the armature or core, etc., is continuous. Accordingly I havedevised the hereinafter described circuit breaker containing a specialnovoltage magnet of peculiarly eco nomical and simple construction,which,

taken with the novel cooperating mechanical arrangements of parts,accomplishes the main object referred to and also requires but littleenergy to hold the armature, and,when the armature trips, carriessutlicient force to open the circuit breaker.

The constructional details, operation, and further advantages of myinvention will appear more at length in the course of the followingdescription, taken with reference to the accompanying drawings, in whichI have shown a preferred embodiment of the.

apparatus.

lnxthe drawings, Figure 1 is a view there of in side elevation, the oilpan being shown in transverse section, and certain parts broken away forclearness of illustration; Fig. 9 is a view thereof looking toward theleft, Fig. 1, parts being broken out to show constructional details;Fig. 3 shows in edge view the special bobbin or coil for theelectro-magnet; Fig. 4 is a transverse sectional view showing theconstructional details of the no-voltage magnet; 5 shows in frontelevation the magnet casting; and Fig. 6 is a fragmentary view in sideelevation of a portion of the part shown in As already intimated, theprincipal feature of my present invention is the magnet (and cooperatingmechanism), which is of an armature type and made entirely of cast-,cuit and therefore constantly consuming iron, the core and the shellbeing integral, and the latter, which constitutes the outside of themagnetic circuit, preferably furnishing a complete cover for the coil toprotect the same from mechanical injury. Although cast iron is acomparatively poor magnetic conductor, it is likewise an extremely poorelectric conductor, and I take advantage of this latter fact, inconnection with certain structural details to be explained later, toprovide an alternatingcurrentmagnet which will not unduly heat, theelectric resistance of cast iron being so high that the eddy currentsset up in the iron will not overheat the iron, but become beneficial.These eddy currents in the cast iron set up innumerable fluxes out ofphase with each other, giving a practically constant pull, and thereforeentirely obviating the humming previously re ferred to. The weight ofthe armature also helps toward noiseless operation, as, because of itsinertia, it requires appreciable time to move, and, therefore, even ifthe current should momentarily drop, let it'be supposed, entirelyto'zero, it would cause no percep tible humming. I employ a large massof cast iron having large radiating surfaces and keeping the fluxdensity low, the shape of the magnet giving a large area of air-gap, andthe core, integral with the rest of the casting, reducing the magneticreluctance to such an extent that the device is extremely economical.The latter is an important feature in connection with alternatingcurrent no-voltage release as it is constantly in cir- 99 energy. Theefficiency is improved by the arrangement of the armature whoseetfectire weight is comparatively small when. closed and large when itfalls away from the closed position, so that a small magnetic energytends to keep it in its closed position. Having premised this much as tothis leading feature of my invention and its theoretical and practicalvalue and importance, the preferred embodiment of the invention will nowbe explained, it being understood that my invention is not limitedthereto but is capable of a wide variety of mechanical embodimentswithin the spiritand scope of the invention as herein set forth andhereinafter claimed.

Secured to a switch board or; other support 1 is a bracket 2 having ahorizontal ledge or switch support 3 and an upright portion 4 which, asherein shown, is secured to said board or wall 1 by bolts 5, (3.Depending from the support 3 is anoil pan or well 7 of usual orpreferred construction, containing stationary contacts 8 and movablebridging contacts 9 corresponding in number and arrangement to thecircuit system for which the switch is provided. The movable bridgecontacts 9 are secured to a block 10 carried by a post 11 pivotallyconnected at 12 with the upper ends of toggles, the meeting ends ofwhose links 13, 14am pivoted together at 15, the link 14, being .mountedon a tilted pivot at 16, and the pivot 12 of the upper link being freeto slide in a vertical slot 17 in a rigid standard 18.- A handle lever19 provided with a handle 20 ispi-voted at 21 and serves. to move alatch plate or bar 22 freely pivoted on a transverse pivot pin 23 whichextends through said handle lever 19 beyond the latter at its oppositeends in position to engage stops 24 projecting rigidly upwardly andrearwardly from stationary oblique braces 25 which constitute a part. ofthe supporting frame of the apparatus. The latch plate or bar 22 isshown as having a notch 26 with an obliquely inclined front Wall orwedging surface for breaking the toggle when suddenly tripped or swungupward on its pivot 23, said notch embracing or catching over the togglepivot pin 15 of the toggles for raising and lowering the movablecontacts 9 when it is desired to close or open the switch. Pivoted at 16is a tripping arm or lever 27 shown as provided. with a lifting stop orcampro- 'jection 28 inposition to engage the free end of the latch plate22, and to the free end 29 of said lever 27 is pivotally connected alink 30 pivoted to the free end of an armature lever 31, herein shown asin the form of integral ears mounted on a pivot 32 between projectingflanges or vertical ribs 33 of the part .4. Said armature lever carriesa vertical armature 34 of the cast iron electromagnet or no-voltagerelease device previously referred to at length, and'shown in enlargeddetail in Figs. 3-6. The armature is limited in its falling movement bya stop 35. The core 36 and shell or casing 37 ,of said electro'magnetareintegrally formed in one casting, provided with an annular space 38 forreceiving a spool 39 and coil 40 which complete the electro-magnet. Asherein shown, said spool and its winding are secured fixedly in place byscrews 41 mounted in recesses 42, and the casting which constitutes thecasing or shell of the electromagnet is provided with an oblique hole 43through from front to back whence a groove 44 leads out, for receivingthe lead or terminal 45 from the inner end of the coil, the outer leador terminal 46 passing out through a groove 47. As herein shown, adiaphragm or thin plate 48 of non-magnetic metal secured by screws 49 tothe face of the armature 34 to keep the same from contacting with thecore and sticking thereto, and the latter is provided with a handle 50for its hand operation. This electro-niagnet which constitutes-theno-voliage release of the circuit breaker is mounted verticz'illy overthe circuit bI'QHkQPSO that the heavy mass of the armature 34 is almostover its pivotal center when in closed position and, upon beingreleased, falls toward the horizontal sutliciently to render its -weightelt'ective in tripping the circuit breaker. Preferably the circuitbreaker is also provided with a usual overload coil and tripping core 52in position for its'tripping pin to strike against the under side of thelever 27 and thereby trip the circuit breaker in obvious manner. Themovement. of the lever 27 under the impulse of the tripping pin 53effects actuation of the circuit breaker without disturbing the armature34 by reason of a lost-motion device, preferably in the form of a pinand slot connection at the upper end of the link .30.

The operation of the circuit breaker is as follows: To open it by hand,the handle 20 is swung to theright, Fig. 1, thereby breaking the toggle1 3, 14 and loner-ing the post 11 and the movable contacts 9 awaytromthe fixed contacts 8. To close the circuit breaker, the armature 34 ofthe no-voltage release is first raised into its full line position asshown in Fig. 1, thereby moving the tripping arm 27 and projecting cam28 down out of the path of the latch plate 22, and then while theseparts are held in said posi tion, the switch handle 20 is raised ormoved forward to the left to the position shown in Fig. 1, tl'ierebyrestoring the toggles to their vertical position and closing thecontacts 9 against the contacts 8. As long as the current is passingproperly through the circuit breaker, the armature 34is held in itsraised or closed position as shown in full lines in the drawings, andall humming is obviated by reason of the fact that the no-voltagerelease device or magnet is made of cast iron, so that the eddy currentstherein produce a practically constant pull on the armature and henceprevent the latter from chattering or humming. Also, as the magnet is ofthe armature type and the latter has large mass, also of cast iron, itis necessarily sluggish in response to variations of current in thecoil. The large mass of the magnet core and case, and hence the largeradiating area thereof, keeps the flux density low and prevents undueheating. By having the core and case integral, as distinguished frombeing riveted or screwed or otherwise secured to each other as separateparts, the magnetic reluctance is reduced so as to render the operationeconomical. although the magnet is continuously in circuit and thereforeconstantly consuming energy, and this result of economy isstlll furtheraided by the vertical arrangement and construction of the armature andmagnet whereby small magnetic energy keeps the armature in closedposition and yet eflective weight is available to trip the breaker whenthe armature falls. the armature falls to its dotted line position, Fig.1, it thereby raises the tripping cam or stop 28, which lifts the latchplate22, so that as it moves out of engagement with the toggle pin 15the} inclined front wall of its notch 26 breaks the toggleand permitsthe circuit breakerto open. As long as the armature remains down andhence the cam stop 28 remains up, the latch plate 22 cannot be engagedwith the toggle pin 15 but whenreciprocated simply moves idly by thesame. The special arrangement of separating the leads orcoil terminalsof the magnet rendersthe apparatus still more simple, economical andcertain, as thereby the-internal lead 45 does not cross the outside lead46 but is brought from the center of the core through the slot 43, 44 tothe outside of the magnetic shell with the whole width ofthe coil andmagnet between them so that, although the full voltage is between saidtwo leads or wires, the usual danger of breaking or puncturing the coilis eliminated.

Having described my invention, what I claim as new, and desire to secureby Letters Patent is:

1. In an alternating current electromagnetic switch, contacts, and acast .iron armature having sufficient size and mass to prevent hummingand overheating connected for controlling the same.

I 2. An electromagnetic switch, for use in normally closed alternatingcurrent circuits, comprising circuit controlling contacts, anelectromagnet'having.an armature connected for controlling saidcontacts, the magnetic circuit of said magnet being composed of highelectric resistance magnetic material of crystalline texture havingrelatively large area and low flux density and being of sufficient sizeand mass to prevent overheating and humming when used in a closedmagnetic circuit. o

3. An electromagnetic switch for alternating current circuits,comprising circuit controlling contacts, a magnet having a cast ironcore, and a cast iron armature of suiii-v cient size and mass to preventhumming and WVhen overheating cooperative therewith connect ed forcontrolling said contacts.

4. In an alternating current electromagnetic switch, circuit controllingcontacts, and an electromagnet, having a relatively large cast ironcore, an integral cast iron casing, and acast ironarmature of sufficientsize and mass to prevent humming and overheating, said armature beingconnected for controlling said contacts.

5. In combination an alternating current circuit, an electromagnethaving a cast iron armature of suflicient size and mass to preventhumming andoverheating with its coil mass to prevent humming andoverheating pivoted to stand substantially vertical when in closedposition, mechanism for controlling said circuit, and aconnection fromsaid armature for governing the same.

7. The combination with anormally closed alternating current circuit, ofa tripping electromagnet connected therein having a relatively largecast iron core, integral cast iron casing and massive cast ironarmature, said cast iron 'parts being of a size and mass to preventhumming and overheating of the, armature, a mechanism for controllingsaid circuit, and a connection from said armature for governing thesame.

8. An alternating current system of control for electric circuits,consisting of a controlling device biased to remain closed when fullvoltage is present on said system, and tripping means for saidcontrolling device, consisting of a magnet of cast'iron constructionhaving a mass and proportions adapted to .prevent humming andoverheating with a closed magnetic circuit, said magnet operating togovern said controlling device upon the cessation of the voltage flow.

In testimony whereof, I have signed my name to this specification, inthe presence of two subscribing witnesses.

CHARLES C. BADEAU.

Witnesses M. J. SPALDING, EDWARD MAXWELL.

